If you don’t check in 24 hours before your flight, there’s no need to panic, but it can lead to a few inconveniences depending on the airline and the type of ticket you have. Most airlines open online check-in 24 hours before departure as a convenient way for travelers to secure their boarding pass, choose or confirm seats, and save time at the airport. However, if you forget or are unable to check in during that window, you can still check in at the airport, either at the airline’s check-in counter or using self-service kiosks, if available. Keep in mind that airport check-in typically closes 45 to 60 minutes before domestic flights and 60 to 90 minutes before international flights, so it’s important to arrive early enough to complete the process.

One downside of not checking in early is that you may lose access to preferred seat selections. Many airlines allow early check-in passengers to choose better seats or pay for upgrades, and waiting until the last minute can limit your options. If your flight is full, you might be assigned a middle seat or placed in an undesirable location. In some rare cases, especially with budget airlines or on oversold flights, passengers who check in late may be at risk of being denied boarding if the airline gives priority to earlier check-ins.

Not checking in early can also lead to longer wait times at the airport, particularly during peak travel hours. If you haven’t checked in online, you’ll need to wait in line at the counter or kiosk, which can be time-consuming and stressful. You may also have less time to pass through security and reach your boarding gate, increasing the risk of missing your flight. This can be especially problematic at large or busy airports, where the distance between check-in, security, and gates can be significant.

Additionally, for international flights, checking in late can complicate things if your travel documents need to be verified. Airlines often need to confirm that passengers have valid passports, visas, or health documents before issuing a boarding pass. If this process is delayed due to late check-in, you might not have enough time to complete immigration and security checks.

Some airlines have stricter rules and may charge fees or close check-in earlier than expected, especially for basic economy or low-cost fares. Not following the recommended check-in time could result in losing your seat or having to rebook your flight at your own expense. Also, passengers who check in late are less likely to receive advance updates about gate changes, delays, or other flight details.

In summary, not checking in 24 hours before your flight won’t necessarily prevent you from traveling, but it can lead to seat limitations, longer wait times, added stress, and even missed flights. To avoid these issues, it’s best to check in as early as possible—whether online, through the app, or at the airport—to ensure a smooth, hassle-free travel experience.